The hazards to public health and the environment which are posed by a variety of halogenated organic compounds are well known. Compounds such as polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane (DDT), trichloroethylene (TCE), and chlorinated benzenes have been regulated as environmentally toxic compounds. Due to spills and prior usage, these compounds are often found in soil, sludge and building materials. Their disposal requires a safe and efficient means.
Polychlorinated biphenyls pose a potentially serious environmental problem. Once widely used as dielectric fluid additives in electrical equipment for transformers and capacitors, the use of PCBs has been banned by the U.S. Environmental Protection Agency. Trichloroethylene is ranked as a targeted chemical for clean-up due to its widespread usage as a degreasing solvent. Thus, methods for the removal and destruction of PCBs, trichloroethylene and other chlorinated solvents from contaminated waste sites are sought.
The costs associated with the characterization and remediation of these waste sites are exceedingly high. Various thermal methods for the removal or destruction of halogenated organic compounds, such as incineration, are currently used. Toxic by-products are sometimes produced with this method. An alternative method is soil washing of contaminated materials. The treating chemicals in this method sometimes may pose potential secondary environmental problems. Also, current destructive methods often do not address situations where trace quantities of pollutants are found and need to be destroyed.
There are also problems with the detection of chlorinated hydrocarbons at waste sites. Methods exist for trace analysis of chlorinated hydrocarbons in laboratories, not for rapid and simple detection in the field. These laboratory methods usually require expensive instruments, well-controlled operation conditions, and lengthy sample preparations. These analysis procedures are time consuming and expensive.
Thus, a need exists for a method to remediate contaminated materials which do not require excessive amounts of various reagents, do not produce toxic by-products, is relatively inexpensive, and obtains acceptable removal and destruction levels of contaminants.